Conference proceeding
Post-glacial melt generation in southern Chile and the development of the Carran-Los Venados volcanic field (40'20 degrees S)
p.707
IAVCEI 2023 Scientific Assembly
2023
Abstract
The Carran-Los Venados (CLV) volcanic field (40'20 degrees S) in the Southern Volcanic Zone of Chile has been volcanically active from approximately 5 ka to its last eruption in 1979 CE. It consists of approximately 70 basaltic scoria cones and maars, constructed over extensive late glacial to early postglacial basal basaltic lava flows. Mafic rocks erupted in this setting therefore provide an ongoing record of melt generation associated with deglaciation. Whole rock major and trace element compositions combined with U-Th and Sr-Nd-Pb isotopic ratios and olivine compositions show a profound difference between the basal lavas underlying the volcanic field and the later monogenetic basalts. Differences in fluid mobile/immobile element ratios and incompatible trace element contents, in addition to changes in olivine Fo contents suggest that the former were produced by melting of a drier, more enriched source, whilst the monogenetic field was sourced by a significantly wetter, more depleted source. The most recent eruption within the field (Mirador) displays characteristics of both sources. We hypothesize that deglaciation drove the decompression and subsequent melting of relatively dry and enriched mantle at higher upwelling rates allowing the eruption of extensive lava flows. As deglaciation slowed and upwelling rates decreased, more isolated fluid-fluxed melting events dominated magma genesis. This change occurred over a narrow window of time--a few thousands of years--suggesting that in such conditions shifts in melting dynamics and eruption style can occur relatively rapidly.
Details
- Title: Subtitle
- Post-glacial melt generation in southern Chile and the development of the Carran-Los Venados volcanic field (40'20 degrees S)
- Creators
- Lucy McGee - University of AdelaideKaty Chamberlain - Teesside UniversityMark Reagan - University of Iowa
- Resource Type
- Conference proceeding
- Publication Details
- p.707
- Conference
- IAVCEI 2023 Scientific Assembly
- Publisher
- International Association of Volcanology and Chemistry of the Earth's Interior
- Alternative title
- IAVCEI 2023 book of abstracts
- Language
- English
- Date published
- 2023
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9984805011402771
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